At present, digital products have been widely used in all aspects of people's lives, where digital cameras are indispensable companions at a party or during people's tour. When photos are taken by a digital camera, various reasons may cause poor quality of these photos, such as color overload, red eye of a person, overexposure, bad layout and/or poor definition. Therefore, some photos may become condemned photos. In the process of implementing an embodiment of the present invention, the inventor, however, finds that the existing technology at least has the following problems: Photos of good quality and poor quality can be distinguished only through manual selection, and the people are greatly inconvenienced by a number of photos for selection. That is, photo quality cannot be evaluated with the existing technology.